Manure-biochar compost mitigates the soil salinity stress in tomato plants by modulating the osmoregulatory mechanism, photosynthetic pigments, and ionic homeostasis

One of the main abiotic stresses that affect plant development and lower agricultural productivity globally is salt in the soil. Organic amendments, such as compost and biochar can mitigate the opposing effects of soil salinity (SS) stress. The purpose of this experiment was to look at how tomato growth and yield on salty soil were affected by mineral fertilization and manure-biochar compost (MBC). Furthermore, the study looked at how biochar (organic amendments) work to help tomato plants that are stressed by salt and also a mechanism by which biochar addresses the salt stress on tomato plants. Tomato yield and vegetative growth were negatively impacted by untreated saline soil, indicating that tomatoes are salt-sensitive. MBC with mineral fertilization increased vegetative growth, biomass yield, fruit yield, chlorophyll, and nutrient contents, Na/K ratio of salt-stressed tomato plants signifies the ameliorating effects on tomato plant growth and yield, under salt stress. Furthermore, the application of MBC with mineral fertilizer decreased H2O2, but increased leaf relative water content (RWC), leaf proline, total soluble sugar, and ascorbic acid content and improved leaf membrane damage, in comparison with untreated plants, in response to salt stress. Among the composting substances, T7 [poultry manure-biochar composting (PBC) (1:2) @ 3 t/ha + soil-based test fertilizer (SBTF)] dose exhibited better-improving effects on salt stress and had maintained an order of T7 > T9 > T8 > T6 in total biomass and fruit yield of tomato. These results suggested that MBC might mitigate the antagonistic effects of salt stress on plant growth and yield of tomatoes by improving osmotic adjustment, antioxidant capacity, nutrient accumulation, protecting photosynthetic pigments, and reducing ROS production and leaf damage in tomato plant leaves. Supplementary Information The online version contains supplementary material available at 10.1038/s41598-024-73093-5.

evaporation.Soil salinization 4 affects approximately 1,128 million hectares of land worldwide, and secondary salinization has added 77 million hectares of land 5 .Approximately 20% of all farmed and 33% of irrigated agricultural fields globally are affected by soil salinization 6 .Estimates of the global distribution of regions impacted by salt indicate that 50.8 million hectares are in Europe and 87.6 million hectares are in South Asia 7 .Comparably, 30% of Bangladesh's farmland area roughly one million hectares is damaged by salinization to varied degrees 8,9 .Salinity-induced losses in crop production cause irrigated agriculture to lose USD 27.2 billion annually in economic value.Abiotic stress, such as salinity/drought simultaneously causes ion toxicity, osmotic stress 10 , and oxidative stress 11,12 , which affect the physiological and biochemical processes of many plants, including photosynthesis 13 , energy metabolism, plant water, nutrient uptake imbalance 14 , protein 15 , DNA, membrane damage 16 , etc., and ultimately affect the growth 17 and yield of crops 18 .Osmotic stress in plants changes many enzymatic antioxidants, such as CAT, SOD, GOPX 11 , non-enzymatic antioxidants, such as carotenoids 19,20 , betalains 21,22 , ascorbic acids 23,24 , betaxanthins 25,26 , chlorophyll a 27 , betacyanins 28 , chlorophyll b 29 , xanthophylls 30 , beta-carotene 31 , phenolic and flavonoids, such as hydroxycinnamic acids 32 , hydroxybenzoic acids 33 , flavanols 34 , flavones 35 , flavanones 36 , flavonols 37 , etc. having high antiradical capacities 38 which can manage the adverse impact of abiotic stresses.Under abiotic stress, the plant itself regulates different pathways to increase the application of these antioxidants 39 to detoxify the ROS 40 and mitigate environmental stress.
Furthermore, SS poses a serious risk to farmland soil production by adversely affecting microbial activity, nutrient availability, and soil characteristics 41,42 .There is usually a 30-50% yield loss, depending on the SS 43 .Plants have developed a variety of defense mechanisms to withstand salinity, including ion homeostasis and compartmentalization, osmoprotectant production, antioxidant activation, and the control of several stresssensitive genes 44 .Various reclamation techniques, including chemical remediation, phytoremediation, soil water leaching, organic amendment, etc., can be used to improve the congenial environment that plants use to withstand stress.Thus, reducing the salt burden on crop growth in appropriate and economical ways has become a top concern in the development of technologies to guarantee global food security.
In salinity-degraded soil, soil management and agricultural production techniques depend on maintaining a suitable level of soil organic matter and guaranteeing the effective biological cycling of nutrients 45 .Organic amendments may be considered a sustainable method of lessening the effects of salinity stress on crops since they have both ameliorative effects and enhance the fertility status of saline soils 46 .Salinity stress can have significant effects on various crops.A high soil salinity level can lead to water stress and ion toxicity, decreasing water availability and increasing the rate of transpiration in plants 47 .In addition, high soil salinity causes ion homeostasis to be disrupted, resulting in an accumulation of toxic ions such as sodium and chloride in plant tissues 48 .According to several studies, organic matter's improved physical, chemical, and biological qualities could help reduce salt stress 49,50 .However, adding organic matter won't be able to sustainably improve this deteriorated soil in the tropics because of the natural quick degradation of organic matter and poorly stable chemicals 51 .Almond shell-derived biochar (ASB) induced changes in soil microbial composition and communities 52 .The use of more stable carbon compounds, such as carbonized materials, is an alternative to organic additions.Because of its strong Na + adsorption potential and relatively stable nature, the biomass product known as "biochar, " which is produced through anaerobic or limited oxygen condition pyrolysis, may be able to reduce salinity stress 53,54 .Because of its increased ability to add Ca 2+ and Mg 2+ , improve the physical characteristics of the soil, including aggregate stability, porosity, saturated hydraulic conductivity, and bulk density, and consequently improve Na + leakage, biochar becomes an efficient remediation approach in salty soil 55 .However, due to its expensive and unusual production methods, there is limited data available on the practice of biochar as a viable soil additive for salty soils.For agriculture that is susceptible to salinity stress, appropriate and economical methods of minimizing the negative effects of salt stress on crop growth have thus become crucial.The study reported that biochar-manure compost (poultry manure mixed with biochar (1:3) in conjunction with pyroligneous solution had significant positive effects on salinity reduction in cereals like maize productivity 54 .However, further research is needed to elucidate the effects of different manure and biochar compost combinations on salt-sensitive vegetables, such as tomatoes.Thus, we hypothesize that composting manure and biochar can reduce salt stress and will be a cost-effective strategy for tomato growers in salinesensitive locations.Different crops have varying levels of salt tolerance.Some crops, like barley, sugar beet, and spinach, are more salt-tolerant and can withstand higher levels of salinity.On the other hand, crops such as tomatoes, eggplant, beans, and many fruit trees are more sensitive to salt stress 56 .
The majority of Bangladesh's salinity-affected areas experience seasonal flooding from salt water, which varies the degree of salinization of the soil.The majority of the land remains fallow during the dry season because of the elevated salinity of the soil and the shortage of high-quality water 57 .One of the most significant and nutrient-dense foods grown in arid, salinity-degraded agricultural regions maybe tomatoes.The Solanaceae family includes the tomato (Lycopersicon esculentum L.), most of which are cultivated in nearly every part of the globe.It ranks as the second most significant crop among the 24 vegetable crops.Tropical, subtropical, and even temperate regions of the world are where it is primarily farmed 58 .Due to their flavor and nutritional worth, tomatoes are an essential part of the human diet.Because of its short root structure, high stomatal conductance, and wide diversity of leaf types, the tomato plant is the most vulnerable to salt stress 59 .If we are to convert a large number of saline soils under circumstances of intensive agriculture and adapt to climate change, we must comprehend the impacts of salt stress and find measures to decrease it.There is scarce information on the effects of salt stress on tomatoes as well as the affordable and practical methods of lowering the effects of salt by organic amendment.This study aims to assess the possibility of mitigating SS stress with the addition of compost made of manure and biochar, as well as the mechanisms involved.

Results
The effects of different fertilizers -biochar compost and organic materials on tomato plants under SS stress were studied, including vegetative development, photosynthetic pigmentation, oxidative damage, and their osmotic adjustment properties, leaf nutrient content, biomass, and fruit yield characteristics.

Growth traits
Tomato plants grown in untreated saline soil had lower plant height (PH) (40.20 cm), number of branches per plant (NBP) (2.89), number of leaves per plant (NLP) (19.17), and leaf area (LA) (49.90 cm 2 ), hence exhibiting significant inhibition of plant growth (Fig. 1).The application of different manures, rice husk biochar, and their composting significantly improved the growth characteristics of salt-stressed tomato plants (Fig. 1).
No significant changes in tomato plant yield characteristics were observed with absolutely SBTF-based fertilization compared to unamended saline soils.
374.53%, compared to absolute saline soil plants (Table 1).Manure-biochar compost-treated plants produced higher tomato yields than other organic amended plants under salt stress.

Biomass yield of tomato plant
Manure-biochar compost and its organic matter had significant effects on above-ground biomass (FAGB), dry above-ground biomass (DAGB), fresh below-ground biomass (FBGB), dry below-ground biomass (DBGB), and total dry mass (TDM) (Table 3).Untreated saline soil showed significantly decreased tomato biomass yield.The organic amended plants showed higher fresh and dry biomass compared to abandoned saline soil (control treatment).The T 7 -treated tomato plant gave the maximum FAGB, FBGB, DAGB, DBGB, and TDM production (72.1).

Response in osmoregulatory physiological traits
Salt stress considerably declined the RWC of tomato plant leaves, the lowest content in the T 1 treatment (63.48%).
Adding organic amendment plus SBTF fertilizer increased the RWC (%) of salt-stressed plant leaves, with the superiority of manure-biochar composted treatments (Table 5).
MDA content was reduced in T 9 treated plants.Salt stress caused severe impairment of membrane stability by enhancing the electrolyte leakage (34.56%) in tomato plant leaves (Table 6).This reduction was significantly mitigated by the application of MBC amendment and SBTF-based fertilizer.Minimal electrolyte leakage (13.80%) was calculated for T 9 treatment.The statistically identical finding was recorded in treatment T 6 (17.51%),T 7 (15.18%),and T 8 (17.26%).No significant improvement in electrolyte leakage was observed in plants treated with SBTF fertilizer alone.
MBC and its raw organic materials amended salt-stress tomato plant leaves showed a significant decline in total soluble sugar content.Plants grown in T 9 (CBC (1:2) @ 3 t/ha + SBTF) amended saline soil produce the highest leaf TSS concentration (39.66 mg/g).

Nutritional status of the tomato
Table 8 displays the results of the effects of MBC and its sole raw materials on the nutrients of tomato leaves under salt stress.Statistically noteworthy variances in the N, P, K, Na content, and K/Na ratio were found in organic amended tomato leaves.The N and P contents were highest in tomato leaves under T 7 treatment (18.23 and 4.90 mg/g, respectively).While the T 9 -treated plant leaves in SS condition gave the maximum K content (14.80 mg/g).Similar leaves K concentrations were found in T 6 (13.57mg/g), T 7 (14.74mg/g) and T 8 (13.30mg/g) amended salt-stressed tomato plants.Untreated SS tomato plants in T 1 treatment showed the lowest leaf nutrient contents of N, P, and K (9.29, 2.20, and 7.16 mg/g, respectively).Various organic amendments negatively influence the leaf Na accumulation.The T 9 amended SS plant leaves exhibited the minimum Na concentration (6.03 mg/g), while the maximum Na content (12.47 mg/g) in T 1 treatment.
The K/Na ratio of manure-biochar compost and its raw material and/or SBTF-fertilized plants increased compared to abandoned saline soils (Table 8).

Discussion
One of the biggest risks to crop growth is soil salinization, which lowers crop yields significantly all over the world 60 .The findings demonstrated that tomato plant development and biomass productivity were significantly reduced by soil salinization (Fig. 1; Table 3).This might be because low turgor pressure brought on by salinity prevents cells from expanding, which lowers shoot development and growth.Elevated salt stress has the potential to trigger the synthesis of inhibitors such as abscisic acid and impede the development of growth promoters for plants 61 .Furthermore, salinity inhibits root system growth, altering its morphology and physiology.These modifications result in altered water and ion absorption, ultimately reducing plant growth 62 .The decrease in compound leaves and leaf area may be due to the salt-induced osmotic effect, which reduces the availability of water and nutrients to the roots and eventually disturbs the plant tissues.This would lead to a decrease in meristematic tissue activity and cell expansion 63 .Merely applying chemical fertilizer cannot compensate for the decrease in biomass production brought on by salt.The application of MBC and its organic components reduced the impacts of salt stress and led to a noteworthy increase in the vegetative attributes of tomato plants under SS stress, including PH, NBP, NLP, LA, and biomass, demonstrating its processes of mitigating salt stress (Figs. 1 and 2; Table 3).The growth and biomass output of tomato plants under salt stress were enhanced by the application of organic amendments, which also increased the soil's organic matter and increased hydraulic conductivity, nutrient availability, soil bulk density, and soil water hold capacity 64 .Improved ionic balance and stressed plants' physiological efficiency are guaranteed by increased leaf proliferation in tomato plants grown in salinized soil amendments 65 .Noteworthy differences among traits were demonstrated for ANOVA of our study which were corroborative to the results of agronomic traits of lentil 66 , field pea 67 , mungbean 68,69 , Zea mays 70,71 , Oryza sativa [72][73][74][75][76][77] , Amaranthus spp 78,79 .
directly affects higher membrane damage, called MDA accumulation, which plays a crucial role in increasing the EL of tomato plant leaves (Table 6).SS increases ROS production, thereby damaging cell membranes and causing a significant increase in EL 81 .The substantial reduction in EL in MBC-treated tomato plants indicates a betteralleviating effect of compost treatment, which was associated with lower MDA and H 2 O 2 (Table 6) 2 .Under SS, various organic amendments reduced ROS production, ultimately alleviating MDA accusation by reducing oxidative stress in tomato plants 1 .Tomato plants regulate and increase osmolyte biosynthesis and maintain Na + refflux to counteract the toxic effects of salt stress 64,82 .In the current study, the concentration of proline, soluble sugar, and ascorbic acid in tomato leaves of salt-stressed tomato plants was lower, indicating lower adaptability (Table 7).A key component of plants' defense mechanisms against salt stress is osmoregulation.Under salt stress, plants create osmotically active solutes (like proline) to promote protein biosynthesis or metabolism 26 and balance water potential 83 to protect themselves from abiotic stress.To control osmotic pressure, a significant amount of osmolytes, such as soluble carbohydrates and proline, build up in the cytoplasm and other organelles 59 .
The application of MBC resulted in higher proline biosynthesis in the leaves of tomato plants exposed to SS (Table 7), suggesting that balanced osmosis protects their photosynthetic machinery.In addition, amended tomato plants can accumulate larger amounts of proline to scavenge ROS, reduce oxidative damage, and protect cell membranes from the negative effects of salt stress.Higher proline accumulation in MBC-treated soil may be due to salt-induced increases in N content and metabolism 84 .Under saline conditions, MBC and its raw materials increased the content of alternative important osmolytes, namely TSS, in the tomato plant leaves (Table 7).A substantial increase in sugar accumulation in amended plants indicates effective protection of tomato plants exposed to salt stress.Total soluble sugar plays key roles in many physiological and biochemical processes, including chlorophyll content, scavenging of ROS, and induction of damaging salt-stress conditions in adaptive pathways 85 , Studies have shown that proline and ascorbic acid are potent antioxidants that can scavenge various types of ROS and protect cells from oxidative damage 86 .Salt-stressed tomato plants treated with MBC showed higher ascorbic acid (AsA) accumulation (Table 7).A higher concentration of AsA indicates its better detoxification capacity against salt-induced ROS production.
Salt stress exerts a notable inhibitory effect on various physiological processes, including seed germination, lateral root growth, and biomass generation, leading to significant yield loss.A significant decline in the morphological, physiological, and biochemical indices of watermelon seedlings exposed to salt stress 87 .Salt stress persuaded higher concentration of Na content in tomato plant leaves but lessened other nutrients like N, P, and K contents (Table 8).The application of organic amendments creates provision for larger N, P, and K uptake, and diminishes the salt-induced harmful amount of Na uptake in tomato leaves (Table 8).Osmotic stress is a common secondary stress of NaCl salinity in many plants that can negatively influence many aspects of plant metabolisms 88,89 .The accumulation of large amounts of Na in plant tissues exposed to saline conditions can have damaging effects on the metabolism of cytoplasm and organelles 64 .Excess Na causes an imbalance in cellular Na and K homeostasis, often resulting in a low Na/K ratio 90 .Maintaining a low Na/K ratio in leaves is an important feature of plant salt tolerance 91 .Under salinity stress, the Na/K ratio increased sharply due to excess Na uptake in the leaves.These results indicate that MBC and other organic amendments can promote nutrient balance and reduce ion toxicity thereby accelerating the vegetative development of plants.One practical method of improving salt tolerance is by high intake of mineral nutrients 92 .Biochar addition reduces plant sodium uptake in salt-stressed soils due to its high uptake capacity through transient binding of Na + and release of mineral nutrients (K + , Ca 2+ , Mg 2+ particles) into solution 93,94 .Therefore, it can be concluded that biochar prevents sodium uptake by plants by releasing nutrients into the soil solution.Biochar might have the potential to release large amounts of Ca and Mg and displace Na + at soil exchange sites, thereby reducing the availability of Na + to plants 95 .Since BC has a larger surface area, CEC, and porosity, the addition of BC hinders the absorption and accumulation of Na +96 .BC application increases Ca 2+ content, thereby improving SS tolerance by altering cell signaling pathways 97 .The application of biochar can reduce the Na/K ratio and Ca 2+ through the Ca 2+ dependent SOS pathway 98 .Sodium elimination in roots occurs primarily through the plasma membrane Na + / H + antiporter, a well-known gene (SOS1) 96 .Overexpression of vacuolar Na + /H + antiporters increase salt tolerance in plants 99 .Adding biochar to soil improves electrochemical properties, such as root zeta potential, thereby increasing nutrient uptake by plants 100 .The suppressing effect of vermicompost as well as biochar might be attributed to the release of toxic compounds such as ammonium and improved soil nutrient and plant growth, leading to plants more tolerant to nematode damage 101 .In addition, the use of manure-biochar compost has a significant positive effect on improving the growth of microorganisms and the release and uptake of nutrients in saline soil, providing a practical option for alleviating salt stress in tomato plant 102 .The presence of plant nutrients and ash in the biochar and its large surface area, porous nature, and the ability to act as a medium for microorganisms have been identified as the main reasons for the improvement in soil properties and increase in the absorption of nutrients by plants in soils treated with biochar 103 .The positive effects of biochar on the interactions between soil-plant-water caused better photosynthetic performance and improved nitrogen and water use efficiency also biochar has the potential to improve the properties of soil, microbial abundance, biological nitrogen fixation, and plant growth.Therefore, it is recommended to use biochar as a soil amendment for long-term carbon sink restoration 104 .These biochars acted as a nutrient source as well as a suitable cation exchanger due to their large surface area resulting in the availability of nutrients and their higher uptake by plant roots 105 .Under SS stress, plants display disturbances in several physiological processes, leading to a decrease in tomato production (i.e., SFW and TFWP) (Fig. 2) and yield attributes (i.e., NFCP, NFC) (Table 2).Tomato output is significantly reduced by SS because it damages photosynthetic pigments, results in ionic imbalance and ROS generation, and decreases nutrient uptake, RWC, and membrane integrity 106,107 .By altering chlorophyll pigments, salinity prevents the buildup of photoassimilates, which lowers tomato output characteristics and, in turn, lowers fruit weight 108 .But when MBC and its organic materials were applied, tomato plants under salt stress produced much more, suggesting that salt stress can be lessened (Table 2; Fig. 2).The previous research demonstrates that the use of organic amendment enhanced the productivity and yield characteristics of tomato plants 109 by improving the physiological mechanism of osmoregulation, photosynthetic efficiency, nutrient uptake, and antioxidant activities, K uptake, and Na/K reduction.Moreover, organic matter enhances the qualities of the soil and provides plants with greater capacity for water absorption, photosynthetic pigments, and biochemical activity.This increases photosynthesis, which is positively correlated with increased fruit yield characteristics and fruit weight 110 .In addition to organic amendment, literature have shown that K amendment increased yield, quality, and drought tolerance in soybean 111 , and mung bean growth, yield, nutrient content, and drought tolerance 112 .Nano iron oxide accelerates growth, yield, and quality of soybean 113 .
In summary, biochar is the best organic amendment to act as a source of soil nutrients for improved tomato growth, crop yield, and environmental benefits.SS lowers photosynthetic pigments, nutrient uptake, and leaf water content while increasing H 2 O 2 , MDA, and Na accumulation.These effects ultimately lower tomato output and plant growth.According to our findings, under salt stress, MBC and its organic matter can enhance tomato output and plant growth.The salt-treated saline soil (PBC (1:2) @ 3 tha −1 + SBTF) had the highest biomass and tomato fruit production.Based on how much salt stress reduces tomato yield, T7 > T9 > T8 > T6 is the order in which MBC treatments are applied.To decrease leaf oxidative damage, MBC was applied.This resulted in an increase in chlorophyll content, leaves' RWC, nutrient absorption, Na/K ratio, antioxidant activity, and osmoregulatory characteristics.MBC also lessened the generation of ROS and Na buildup.Consequently, MBC exhibits its tolerance mechanism to salt stress and has a good impact on tomato plants' growth characteristics, photosynthetic mechanism, and physiological and osmotic adaptation features.Therefore, the combined use of biochar and compost can be beneficial in reducing the detrimental effects of salinity on horticultural crops and increasing tomato productivity in salt-affected soils.Based on our findings, additional research is suggested to explore potential mechanisms involved in the improvement of physiology, growth, and productivity under salt stress.

Planting materials and systems for growth
The investigation was led in a salinity-affected farmer's field in Batiaghata Union, Khulna (22° 41΄ 36.1˝N and 89° 31'56.0˝ E) from December 2018 to March 2019.The site is located under the AEZ of the Ganges tidal floodplain (AEZ 13).The high-yielding indeterminate tomato (Lycopersicon esculentum L.) cultivar BARI Tomato-9 (Lalima) was used.Tomato seeds were surface sterilized with 70% ethanol solution and 5% sodium hypochlorite solution (NaOCl) for 15 min, and then washed with distilled water.For two days, tomato seeds were grown on damp filter paper in the dark.Then sown in sand-filled trays and grown under the transparent plastic shed for 10 d.At the second-leaf stage, the seedlings were uprooted and placed in plastic bags filled with soil, grown for 20 d, and then transplanted to the experimental field.With soil salinity i.e., ECe (6.62 dS/m), pH (7.52), organic carbon (OC) (0.68%), total nitrogen (TN) (0.09%), available phosphorus (P) (18.40 mg kg −1 ), and exchangeable Ca, Mg, Na, and K (7.44, 3.72, 18.67, and 0.27 cmol kg −1 ), respectively, the soil belonged to the silty clay loam textural class (sand 18.10%, silt 45.30%, and clay 36.60%)(Table 9).The average daily temperature, minimum temperature, and relative humidity for the tomato cultivation season were T max = 34.3°C and T min = 26.2°C; RH max = 95.1% and RH min = 67.3%,respectively.In accordance with our institution's, as well as national and international norms and laws, experimental research, laboratory, and field investigations of the effects of salinity stress on organic amendments in tomatoes, including the collecting of tomato seeds, were conducted.

Manure-biochar compost preparation
Biochar used in field experiments was obtained by pyrolysis of rice straw in a two-chamber pyrolysis furnace at 400-500 °C.Locally collected cow dung and poultry manure were kept in ambient conditions for a week to lessen extra moisture.Table 10 displays the chemical characteristics of the additional organic compounds.
For compost preparation, manuring substances (M) (cow dung (C) and poultry manure (P)) and biochar (B) were mixed at the ratio of 1:1 (M: BC, v/v) and 1:2 (M: BC, v/v).After 6 weeks cow dung-biochar compost (CBC) and poultry manure-biochar compost (PBC) were ready for field application.The produced MBC is thoroughly mixed before use as a soil amendment.

Composition (% (w/w)) pH ECe OC TN P K Ca Mg Na
Sand Silt Clay dS m -1 (%) (%) (mg kg -1 ) (cmol kg -1 ) (cmol kg -1 ) (cmol kg -1 ) (cmol kg  Final land preparation included basal application of one-third of urea, TSP, MP, gypsum, and full volumes of organic amendments.Two top dressing applications of the leftover computed urea were made at 15 and 35 days after transplantation (DAT).We maintained the field capacity (FC) of the soil (moisture content of soil 30.7%) for each pot.Irrigation was provided at 12 h intervals.The moisture loss every day was fulfilled by adding tap water using a moisture meter until the soil moisture level was raised to 30.7%.As we maintained FC (water only in the micropores of the soil), so very minimal water was required every day to maintain FC and there was no leaching or percolation of the potting soil.As a result, the salinity of the soil remains constant throughout the cropping season.The conventional cultivation method used in Bangladesh was followed when applying tomato production to agriculture.

Tomato growth and yield characteristics are measured
During the active flowering period at 65 DAT, several growth parameters [PH (cm), NBP, NLP, and LA] were assessed.Yield characteristics of tomato fruit (NEFC and NFC) were counted in three selected plants and their average value was calculated.Tomato fruit yield was calculated by counting NFP and SFW and weighting all the picked fruits collected at the ripening stage from each plant.Fruits were harvested four (4) times during the harvesting time and that began on 13 March 2019.In the senescence stage, the whole plant, fresh weight (FW), and dry weight (DW) were calculated to obtain biomass yield.To determine the total dry mass (TDM), plants were divided into shoots and roots and air-dried first at room temperature and finally oven-dried at 65 °C for 72 h.

Measurement of pigment content
Using the method outlined by Lichtenthaler et al. 115 , the total chlorophyll content (mg/g FW) was determined from the completely prolonged top most leaf at the flowering stage (67 DAT).To extract leaf chlorophyll, 20 mg of completely inflated leaf samples were taken, put in tubes covered in aluminum foil with 20 mL of 80% acetone, and left in the dark for the entire night at 4 °C.Following centrifugation, a spectrophotometer was used to measure the absorbance at 645 nm and 663 nm wavelengths.

Measurement of electrolyte leakage and water status
The Sullivan 116 method was used to measure the electrolyte loss in the leaves at 67 days after harvest.Leaf samples weighing about 0.5 g were collected and placed in two distinct test tube sets, each holding 10 mL of deionized water.The first group was incubated for ten minutes at room temperature, while the second set spent thirty minutes in a water bath at fifty-five degrees.An EC meter was used to determine the electrical conductivity (EC) of the supernatants from both sets.ECa and ECb are the names of the first and second sets of ECs, respectively.
The following formula was used to determine the electrolyte leakage: Electrolyte leakage (%) = {(EC b -EC a )/EC e } × 100.
The technique of Hayat et al. 117 was used to calculate the leaf relative water content (RWC).Samples of fullygrown leaves (at 67 DAT) were collected, and the fresh weight (FW) was measured.To determine the turgid weight (TW), the same leaves were immersed in distilled water for four hours.For 72 h, the leaf samples were oven-dried at 70 °C to obtain a consistent dry weight (DW).The formula used to compute the RWC of leaves was: -RWC (%) = {(FW -DW)/ (TW -DW)} × 100.
salt-stressed soil compared to untreated control.PH = Plant height, NBP = Number of branches per plant, NLP = Number of leaves per plant, LA = Leaf area, NEFC = Effective flower cluster per plant, NFC = Number of fruit per cluster, NFP = Number of fruit per plant, SFW = Single fruit weight, FWP = Fruit weight per plant.FY = Fruit yield, TDM = Total dry mass.

Table 2 .
g and 28.76 t/ha, respectively), T 8 (977.08 g, and 31.27t/ha, respectively) and T 9 (1172.91g and 37.53 t/ha, respectively) treatment.The total FY under the MBC treatments increased by 235.40-Manure and biochar compost (MBC) application impacts on yield and yield attributes of salt-stressed tomato plant.The value indicates the mean (± SD); p < 0. 05; n = 9.Different letters indicate significant differences among treatments ( p < 0.05) by Tukey's HSD test.

Table 4 .
Effects of manure and biochar compost (MBC) on the chlorophyll content of tomato leaf at 68 days after transplanting (DAT) grown in saline soil.The value indicates the mean (± SD); p < 0. 05; n = 9.

Table 9 .
Physico3 t/ha + SBTF.Three replications of a randomized complete block design (RCBD) were employed to order the treatments in the field study.A drainage system of 2.5 × 2.0 m and 0.5 m was built into every plot.On December 5, 2018, four-week-old tomato seedlings were transplanted, with 60 cm × 50 cm spacing between each seedling and two seedlings per hill.The same seedlings were used to repair the gaps one week later.Fertilizers based on SBTF were used to fertilize the crop.computed using Fertilizer Recommendation Guide 114 to yield 321 kg of urea, 85 kg of triple superphosphate (TSP), 22 kg of muriate of potash (MP), and 20 kg of gypsum per ha −1 .